class/Mono.Cecil/Mono.Cecil.Metadata/UserStringsHeap.cs

   1 //
   2 // UserStringsHeap.cs
   3 //
   4 // Author:
   5 //   Jb Evain (jbevain@gmail.com)
   6 //
   7 // (C) 2005 Jb Evain
   8 //
   9 // Permission is hereby granted, free of charge, to any person obtaining
  10 // a copy of this software and associated documentation files (the
  11 // "Software"), to deal in the Software without restriction, including
  12 // without limitation the rights to use, copy, modify, merge, publish,
  13 // distribute, sublicense, and/or sell copies of the Software, and to
  14 // permit persons to whom the Software is furnished to do so, subject to
  15 // the following conditions:
  16 //
  17 // The above copyright notice and this permission notice shall be
  18 // included in all copies or substantial portions of the Software.
  19 //
  20 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  21 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  22 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  23 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  24 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  25 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  26 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  27 //
  28
  29 namespace Mono.Cecil.Metadata {
  30
  31         using System.Collections;
  32         using System.Text;
  33
  34         public class UserStringsHeap : MetadataHeap {
  35
  36                 readonly IDictionary m_strings;
  37
  38                 public string this [uint offset] {
  39                         get {
  40                                 string us = m_strings [offset] as string;
  41                                 if (us != null)
  42                                         return us;
  43
  44                                 us = ReadStringAt ((int) offset);
  45                                 if (us != null && us.Length != 0)
  46                                         m_strings [offset] = us;
  47
  48                                 return us;
  49                         }
  50                         set { m_strings [offset] = value; }
  51                 }
  52
  53                 internal UserStringsHeap (MetadataStream stream) : base (stream, MetadataStream.UserStrings)
  54                 {
  55                         m_strings = new Hashtable ();
  56                 }
  57
  58                 string ReadStringAt (int offset)
  59                 {
  60                         int length = Utilities.ReadCompressedInteger (this.Data, offset, out offset) - 1;
  61                         if (length < 1)
  62                                 return string.Empty;
  63
  64                         char [] chars = new char [length / 2];
  65
  66                         for (int i = offset, j = 0; i < offset + length; i += 2)
  67                                 chars [j++] = (char) (Data [i] | (Data [i + 1] << 8));
  68
  69                         return new string (chars);
  70                 }
  71
  72                 public override void Accept (IMetadataVisitor visitor)
  73                 {
  74                         visitor.VisitUserStringsHeap (this);
  75                 }
  76         }
  77 }